Because it doesn’t have to be. The C++ standard only requires that it is (if memory serves) at least 32 bits wide, and at least as big as int. MSVC (and the ABI used by Windows) defines long to be 32 bits wide, and MingW follows suit because well, the compiler is a lot more … Read more
Note that there is a difference between a cast to long and a cast to Long. If you cast to long (a primitive value) then it should be automatically boxed to a Long (the reference type that wraps it). You could alternatively use new to create an instance of Long, initializing it with the int … Read more
I’ve been tinkering with an approach that (1) multiplies a and b with the school algorithm on 21-bit limbs (2) proceeds to do long division by c, with an unusual representation of the residual a*b – c*q that uses a double to store the high-order bits and a long to store the low-order bits. I … Read more
You’ve exceeded the number of significant digits available (~15 to 16) in double-precision floating-point values. Once you do that, you can’t expect the least significant digit(s) of your result to actually be meaningful/precise. If you need arbitrarily precise arithmetic in Java, consider using BigInteger and BigDecimal.
When writing in C or C++, every datatype is architecture and compiler specific. On one system int is 32, but you can find ones where it is 16 or 64; it’s not defined, so it’s up to compiler. As for long and int, it comes from times, where standard integer was 16bit, where long was … Read more
I think to some extent it was probably an arbitrary decision based on typical use of switch. A switch can essentially be implemented in two ways (or in principle, a combination): for a small number of cases, or ones whose values are widely dispersed, a switch essentially becomes the equivalent of a series of ifs … Read more
Because numbers in JavaScript are floating-point. They have limited precision. When JavaScript sees a very long number, it rounds it to the nearest number it can represent as a 64-bit float. In your script, start and end get rounded to the same value. alert(1234567890123456789); // says: 1234567890123456800 alert(1234567890123456799); // says: 1234567890123456800 There’s no built-in way … Read more
This should do the trick. (It’s an extension method so that you can call it just as you call the normal Next or NextDouble methods on a Random object). public static Int64 NextInt64(this Random rnd) { var buffer = new byte[sizeof(Int64)]; rnd.NextBytes(buffer); return BitConverter.ToInt64(buffer, 0); } Just replace Int64 with UInt64 everywhere if you want … Read more
Credits to http://moeffju.net/blog/using-bigint-columns-in-rails-migrations class CreateDemo < ActiveRecord::Migration def self.up create_table :demo, :id => false do |t| t.integer :id, :limit => 8 end end end See the option :id => false which disables the automatic creation of the id field The t.integer :id, :limit => 8 line will produce a 64 bit integer field
The language guarantees that int is at least 16 bits, long is at least 32 bits, and long can represent at least all the values that int can represent. If you assign a long value to an int object, it will be implicitly converted. There’s no need for an explicit cast; it would merely specify … Read more